1. Field of the Invention
The present invention relates to a plastic bag sealing apparatus, and more particularly, to a plastic bag sealing apparatus with an ultracapacitor power supply circuit.
2. Background
Various types of electrical power supply circuits have been developed and used for supplying electrical power to plastic bag sealers. Conventional power supply circuits for plastic bag sealers include those adapted to receive electrical power from alternating current (AC) power sources and those adapted to receive power from direct current (DC) power sources. Some of these conventional circuits include conventional rectifier circuits adapted to convert AC power into DC power. Some of the conventional rectifier circuits include a capacitor which serves as a low-pass filter to smoothen DC pulses converted from the AC waveform. These conventional capacitors in the conventional rectifier circuits generally have small capacitances, usually in the range of several microfarads. In general, the conventional capacitors in conventional power supply circuits serve only as low-pass filters to filter out high frequency jitters to smoothen the DC pulses, and have capacitances too small to serve as energy storage units for supplying electrical power. A conventional plastic bag sealer usually includes a heating element powered by continuous energy from a conventional power supply circuit. However, the conventional power supply circuit is generally bulky and energy inefficient.
Furthermore, a conventional plastic bag sealer requires a timer or a heat sensor to control the amount of heating generated by the heating element to seal the plastic bags because the power supply circuit itself does not control the amount of energy supplied to the heating element. Moreover, the size, weight and energy inefficiency of conventional power supplies make them unsuitable for implementation in a portable or battery-operated plastic bag sealer. In some countries the AC voltage may not be compatible with the power supply circuit in a conventional plastic bag sealer, and in some areas AC power may not be available. A portable or battery-operated bag sealer with a compact power supply circuit may be desirable for applications such as the preservation of perishable goods at locations in which AC power is not available or is supplied at a different standard AC voltage.
Therefore, there is a need for a plastic bag sealer with a power supply circuit that is sufficiently light and small for portable applications. There is a further need for a plastic bag sealer with a high efficiency of energy conversion for use with low voltage power supplies such as batteries. There is yet a further need for a plastic bag sealer with a power supply circuit that generates a fixed and predetermined energy for each sealing without the necessity for a timer or a heat sensor to control the amount of energy used for sealing each bag.